Conventionally, in a ease where a ship comes alongside another ship, an operator needs to pay close attention to prevent damage to the ship.
In a case where, in, for example, well-known STS (Ship-To-Ship) and FPSO (Floating Production Storage and Offloading), two ships such as crude oil tankers come alongside each other on the sea and loading and unloading are performed between the ships, the ships should be close to each other and moor the ships to each other. Therefore, it is extremely important to design fenders positioned between the ships and a technique of steering a ship by an operator.
For example, in a case where the weather is getting worse, a ship unintentionally approaches to another ship too close even with a technique of an operator. This breaks a fender positioned between the ships, and, in some cases, the ships contact to each other and are damaged.
In particular, in a case where the loading and unloading are performed at night after the ships are moored to each other, it is difficult to visually recognize a state of a mooring rope and fenders positioned on the sea. It is also difficult to know how much load is applied to the mooring rope and the fenders and in what state the mooring rope and the fenders are.
Therefore, the inventors of the present invention previously proposed a method and a system for assisting steering/mooring of a vessel (WO 2008/053887 A (Patent Document 1)).
In a case where ships come alongside each other and in a case where loading and unloading are performed while the ships are being moored to each other, a method and a system for assisting steering/mooring of a vessel, disclosed in Patent Document 1 display information on a positional, relationship between the two ships and information on fenders. Thus, the positional relationship between the ships and a state of the fenders can be easily understood.
There are similar known techniques including: an another ship target display device disclosed in JP-A-2007-4428 (Patent Document 2); an air pressure monitoring device of a pneumatic fender and a centralized control system for the same disclosed in JP-A-2010-175298 (Patent Document 3); and a fender and a management system therefor disclosed in WO 99/20845 A (Patent Document 4).
The other ship target display device disclosed in Patent Document 2 is configured to display positional and detailed information on almost all ships existing in a predetermined region around own ship to make an operator easily understand the positional and detailed information.
In the air pressure monitoring device of a pneumatic fender and the centralized control system for the same, disclosed, in Patent Document 3, a pneumatic fender includes a plurality of pressure sensors. The pressure sensors transmit air pressure sensing signals repeatedly in turn so that transmission states of the pressure sensors are continued at predetermined intervals. Therefore, the air pressure of the pneumatic fender can be continuously monitored.
In the fender and the management system therefor, disclosed in Patent Document 4, information storage means of a transponder provided in each of a plurality of fenders is accessed by a terminal device. Then, information stored in the information storage means is read out, and the read out information is displayed. In this way, the plurality of fenders is managed.